In standard mining operations, openings are made to expose veins of coal or precious metals. In order to reduce the likelihood of an opening collapsing, which in turn, increases the safety of the miners, various systems have been devised to secure the roof of the opening. At the present time, one of the preferred methods of shoring up roofs includes the affixing of plates or boards onto the mine roof which function to support the roof thereby preventing its collapse. In order to affix roof plates or boards to the mine roofs, holes are drilled in the mine roofs with roof bolting machines. Thereafter, bolts are inserted through holes provided in the plates and are then secured in the holes to affix the plates to the roof. The bolts themselves may be secured within the holes by mechanical means. However, when the holes are drilled in friable material such as coal, which is subject to crumbling, it is preferable that a grouting system be used to stabilize the friable material which results in a secure bolting system.
In conventional roof bolting operations, in order to reduce coats, it is preferable to utilize standardized length bolts, and to drill corresponding depth bolt holes. Common grouting systems include the use of a polyester resin and a hardener as a catalyst which may be mixed at the drilling site and pumped into the drilled hole prior to the insertion of the bolt. In order to simplify the task of the operator, various resin capsules have been developed which contain pre-measured quantities of the resin and hardener such that no premixing at the site is necessary. More specifically, resin capsules have been developed which include discrete compartments for housing both the hardener and a resin, respectively. The resin capsules are of a fixed length corresponding to the bolt length and hole depth. In operation, the resin capsule is loaded into the hole and thereafter a bolt is inserted, which functions to rupture the frangible walls of the capsule. Thereafter the bolt is rotated enabling the contents of the capsule to mix and harden to form a two-part plastic system. By this arrangement, the friable walls of the drilled hole are stabilized and a secure bolting system is achieved.
Recently, due to changing economics and the increasing need to augment domestic energy sources, coal is being mined in areas where it was heretofore considered impractical. More particularly, mining is being carried out where smaller veins of coal are to be found. In such cases, it is impractical to provide opening height common when high veins of coal are mines. Thus, roof bolting drills have been developed which are used for "low coal" and can operate in openings which are as little as three feet in height. As can be appreciated, it is extremely difficult to work with longer six foot bolts and six foot resin packages in openings which are only three feet in height. Accordingly, when roof bolting in"low coal", bolt holes are drilled to a depth required for proper roof support. The actual length of a particular drilled hole may vary from two to six feet depending upon the support requirements, the relative strength of the roof materials, and the number of bolts used per square foot. When drilling holes longer than slam height, the standard resin capsule cannot be used, and a viable substitute must be found. The substitute should be capable of use in holes drilled to a variety of different lengths, and should avoid the problems associated with the on-site premixing of components.
Accordingly, it is an object of the subject invention to provide a new and improved resin capsule for grouting an anchor element is predrilled holes of various lengths.
It is a further object of the subject invention to provide a resin capsule consisting of a tubular member having a plurality of pairs of sealing clips disposed therealong at spaced intervals whereby the tubular member may be severed at a point between the clips of any one of the pairs to provide a resin capsule of the desired length.
It is another object of the subject invention to provide a resin capsule which is relatively flexible and may be wound on a reel for mounting on a conventional roof bolting drill to facilitate the placement of the capsule in the drilled hole.
It is still a further object of the subject invention to provide a new and improved method for fixing anchor bolts in bolt holes utilizing the novel resin capsule of the subject invention.